[Dcat Admin]表單無限級select

贴上代码:
<?php

namespace App\Models;


use Dcat\Admin\Traits\HasDateTimeFormatter;
use Dcat\Admin\Traits\ModelTree;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Database\Eloquent\SoftDeletes;

class GoodsCategory extends Model
{
    use ModelTree; //必須
    use HasDateTimeFormatter;
    use SoftDeletes;

    protected $titleColumn = 'name'; //如果表中分類名稱字段名不是‘title’
    protected $orderColumn = 'sorts'; //如果表中排序字段名不是‘order’

    public static function getAll ()
    {
        return self::where('status', 1)->whereNull('deleted_at')->latest('sorts')->get(['id', 'name', 'parent_id']);
    }

    public static function selectOptions(\Closure $closure = null)
    {
        $options = (new static())->withQuery($closure)->buildSelectOptions();

        return collect($options)->all();
    }
}

// GoodsController 中使用
//表單中
$form->select('category_id')
    ->options(GoodsCategory::selectOptions())
    ->saving(function ($v) {
        return $v;
    })->required();

//篩選器中
$filter->equal('category_id')->select(function () {
  return GoodsCategory::selectOptions();
});